Embodiments in accordance with the present invention are directed to computing devices. More particularly, embodiments of the present invention provide a keyboard switch exhibiting desirable properties such as low noise operation. Merely by way of example, the invention has been applied to a keyboard apparatus for a desk top computer, although it can also be applied to a laptop computer, modular computer, and other computing devices.
Computing devices have proliferated. In the early days, large mainframe computers dominated the computing landscape. These large mainframe computers were developed by companies such as IBM Corporation of Armonk, N.Y. Mainframe computers have been replaced, at least in part, by smaller computing devices, commonly known as “PCs.” PCs come in various shapes and sizes. PCs are often run using computer software such as XP™ from Microsoft Corporation from Redmond Wash. Other types of computer software come from Apple Computer of Cupertino, Calif. Smaller PC versions are often called “lap top computers.” Other types of PCs include larger desktop versions. Still other versions of PCs can be found in smaller devices such as personal digital assistants, called PDAs, cellular phones, and a variety of other applications.
All of these computing devices generally require input devices for human users to interact with them. As merely an example, computer keyboards are most commonly used as such input devices for inputting characters, numerals and symbols to electronic devices, particularly to these computing devices such as the PCs. In such keyboards, an input signal is typically generated by manual depression of a key of a keyswitch device.
FIG. 1A is a simplified exploded view of a conventional key switch apparatus 1. FIG. 1B is a simplified top view of the conventional key switch of FIG. 1A. FIG. 1C is a simplified cross-sectional view of the conventional key switch of FIG. 1A.
The conventional keyboard carries two or more key housings 11a located in a keyboard panel 10a. An inner side of key housing 11a includes a sliding portion in squared chimney form.
Key housing 11a is configured to receive key cap 12a. Specifically, key cap 12a includes stem 13a having a squared chimney form in a lower part thereof. Prism 14a of key cap 12a is formed in the four corners of the key cap stem.
The four corners inside prism 14a and housing 11a contact and slide against one another. Lubricating oil may be applied to four corners of housing 11a so that key cap 12a may move smoothly during this sliding operation.
In operation, when a user touches the keys of key cap 12a with a finger, stem 13a descends within the inside of housing 11a. As a result, rubber dome 15a follows and descends, and membrane switch 16a underlying rubber dome 15a is pushed in and a signal is inputted.
For the conventional key switch apparatus 1 shown in FIGS. 1A-C, it is particularly important that the dimension alpha (α) of a sliding part in the chimney formed inside of housing 11a, and distance beta (β) between prisms 14a of key cap 12a are, dimensionally accurate. Specifically, if a clearance between them is too narrow (for example because of lack of stability during forming conditions or construction of these parts from plastic resin), key cap 12a may become difficult to move or even stuck.
On the other hand, when a clearance between the key cap and the housing is too large, a relatively loud noise may result. Specifically, because key cap 12a becomes unsteady, contact noise of four corners of prism 14a and housing 11a arises, and may resonate and be amplified within stem 13a. 
From the above, it is seen that improved designs for key switches for keyboards are highly desirable.